Bushing for electrical conduits.



iran sra-iras ragEN'r anni@ ADNAH MCMURTRIE, or NEW Yoan, N. Y., AssIGNoR To vTiaoivuis & BErrfrs COMPANY,

0E NEW YORK, N. Y., A CORPORATION oF NEW YORK.

BUSHING FOR. ELECTRICAL CONDUITS.

Application filed April 25, 1907.

To all whom t may concern:

Be it known that I, ADNAH MGMURTRIE, of New York, N. Y., have. invented certain4 Improvements in Bushings for Electrical Conduits, of which the'followmg description, in connection with the accompanying drawings, is a specification,- like letters on the drawings designating like parts.

This invention relates to systems of armor for electrical conductors and more particularly to bushings for protecting the ends of the sheaths as I term generically the various forms of tubular armor whether formed as a unitary structure with the conductor and its' insulation, or having a separate identity, as, in electrical conduits so-called; this bushing being provided, in accordance with my invention, with means to secure the sheath to an outlet box or similar electrical conduit member and to insure electrical connection therewith, as required by the Board oi?` Fire Insurance Underwriters in the installation of such armor systems.

The various features of my invention will be illustrated and described fully in the accompanying drawing and specification, and set forth in the claim.

In the drawing, the figure illustrates in vertical section an outlet box of a well known type provided with several bushings in the construction of which my improvements have been embodied.

In the embodiment of my invention selected for illustration and description to enable ready and complete understanding of my improvements, the part designated by the reference numeral 11 is a bushing which may be, and preferably` is, of annular shape as illustrated, and formed of cast metal, sheet metal, or other suitable and convenient material, having an annular protective shoulder 2 to pass the electrical conductors 3, which are thus prevented from abrasion by the jagged end of the sheath, the latter being illustrated in this instance as a well-known form of flexible armored conductor.

Suitable means to secure the bushing and sheath together are provided in accordance with my invention, and in the instance illustrated these improvements take the form of a set screw 5 passing through a threaded aperture 6 in the shank 7 of the bushing, a rm attachment being thus secured with Specification of Letters Patent.

Patented Dec. 29, 1914.

Serial No. 370,118.

mechanical and electrical connection be-A tween the bushing and the outlet box, and these means may be of any suitable and convenlent form, preferably analogous to the set screw 5, for the sake of uniformity in construction of the bushing. Accordingly, I have shown a. screw '11 passing throughl a .seat 9 in the shank portion 10 of the bushmg and entering the threaded hole 8 in the bottom wall 12 of the box adjacent the aperture 13 which in the instance illustrated isthe usual plain, round hole common to boxes of this type.

The bushing thus illustrated constitutes a very simple, inexpensive and efiicient form of mechanical and electrical connection for the parts joined, land of protection for the conductor; aud'I will now describe several modifications in the arrangement of parts.

At 14 I have shown a conduit aperture in the bottom wall of the box, which has a ledge 15 to receive the closure disk 16, which is held in place in the instance illustrated by a bushing 17 provided with an attaching lug 18 slightly lower` than the top ofthe protective shoulder 19 and having an attaching screw 20 seated in a threaded hole 21 in the base of the box. A set screw 22 is provided in the shank of the bushing, as mentioned with reference to the bushing already described, to enable attachment to a conduit.

The box may be furnished with a disk 16 held in place by the bushing 17 and when the diskis to be removed for insertion of a conduit through the aperture 14 the bushing may be removed temporarily, the disk 16 taken out and the conduit inserted, the bushing being secured in place upon the conduit by the screw 22 and the whole-secured to the box bottom by the screw 20.

Upon the rear wall of the box I have shown a bushing 23, similar in essential de- .tails to the bushing 1 already described, and

screw 31 for attachment to the conduit and u annular an attaching screw 3Q seated in the aperture 33 in the side wall of the boX, a protective annular shoulder 34 being provided upon the bushing, and preferably of somewhat less diameter than the shank of the bushing so that the shoulder can fit snugly within the boX aperture 35.

rl`his bushing has the advantage of being substantially 'lush with the wall and may be in the box needs to be utilized.

On the opposite wall of the box, in lan aperture 36, I have shown the bushing 37 provided with an internal thread 38 corresponding to the peripheral contour of the end of the flexible sheath'shown at 4, the bushused when as much as possible of the space,`

ing being secured to the side Wall by a set screw 39 passing through a lug 40. A set screw 41 is also provided for additional f means of attachment between the bushing and said sheath end.

In the center of the box, I have shown the top of bushing 42 unprovided with a protective shoulder but of form and having an attaching screw 43 to be seated in a threaded aperture 44 adjacent to the central box aperture 45, through which it is usual to pass a gas pipe,

y a set screw 46 being provided for attachment of the bushing to the inclosed pipe.

To close the aperture when a pipe is not bottom wall of the` used the bushing may beprovided normally with the closure disk 47 held set screw 46.

Having illustrated and described my invention thus fully and convenient means for carrying the same into eect, it will be understood that I do not limit myself to the specific materials or forms of construction,

in place by the nor in general otherwise than as set forth in the claim read in connection with this specification.

What I cla-im and desire to secure by Let ters Patent is As an article of'manufacture, a bushing li for the purpose set forth, having an apen ture to receive an armor sheath at times, a Vclosing device at times, a set screw carried by said bushing to secure said sheath and closing device therein, and a closing device secured removably in place by said set screw, said bushing having also a binding screw secure it in place when applied to an elec trical conduit member, substantially as scribed. Signed .at New York, in the county State of New York, this sixteenth day ofi April, 1907.

ADNAH MCMURTRIE. Witnesses:

ALEXANDER C. PnoUDFrr, HOBART D. Bn'r'rs. 

